1. Field of the Invention
This invention relates to artificial leather. In one aspect the invention relates to the top layer of an artificial leather multi-layer laminate while in another aspect, the invention relates to a top layer made from a composition comprising a propylene-alpha-olefin copolymer, an olefin block copolymer and a DPO-BSA molecular melt.
2. Description of the Related Art
Artificial leather is a multi-layer structure or laminate typically comprising a bottom fabric layer and at least one of a top skin layer and a foam layer, typically both a top skin layer and a foam layer with the foam layer sandwiched between the bottom fabric layer and the top skin layer. In some embodiments the multi-layer laminate further comprises a polyurethane (PU) coating layer that is adhered to the top layer with a chlorinated polypropylene (PP) primer.
The problem for the typical incumbent top layer formulation is that it comprises 20-50 wt % styrene/ethylene-butylene/styrene (SEBS) so as to achieve the required balance of softness/flexibility, tensile strength and bonding strength with the PU coating. Specifically, for some application(s), like fashion bags, more than 50 wt % of SEBS is necessary to achieve the softness/flexibility (Shore A of about 50 to 60). The addition of SEBS significantly increases the cost of the finished product which, in turn, hinders the successful commercialization of the product. Moreover, for some applications like furniture leather, abrasion resistance is a stringent requirement.
The artificial leather industry has a continuing interest in the development of low cost, top layer formulations for polyolefin-based applications, especially for fashion bags. These new formulations should achieve the required balance of the softness/flexibility, tensile strength, bonding strength, abrasion resistance, etc., without sacrificing processability during the manufacturing steps, e.g., compounding, calendaring and lamination.